Figure 4.

Rod bipolar cells and horizontal cells. PKC staining of rod bipolar cells in vertical sections shows the expected array of cell bodies lying in the outer aspect of the INL, sending chandelier-like dendritic arborizations to the OPL. The axons of RBCs run a vertical course to terminate in large, bulbous endings, in the innermost part of the IPL, partially intermingling with cell bodies of GCs. All the main morphological features of RBCs are clearly unvaried in the retina of the Pax6α:Cre; Brn3b^CKOAP/KO mouse shown here (A vs B). The dendrites of horizontal cells labeled by calbindin antibodies (red signal) interdigitate with dendrites of cone bipolar cells (arrows) stained by ZNP1 antibodies (green signal). Some horizontal cell processes in the OPL are colabeled and appear yellow. This fine dendritic architecture can be observed in both Pax6α:Cre; Brn3a^CKOAP/KO and Pax6α:Cre; Brn3b^CKOAP/KO (C,E) as well as control mice (D,F) without visible differences among the strains. GCL, ganglion cell layer; INL, inner nuclear layer; IPL, inner plexiform layer; ONL, outer nuclear layer; OPL, outer plexiform layer. Scale bar = 20 µm in B (also applies to A) and F (applies to C–F).